Protective liner for a ball cap



FIG. 1 is a first perspective view of a protective liner for a ball cap in accordance with our design;

FIG. 2 is a second perspective view thereof;

FIG. 3 is right side elevation view of the protective liner for a ball cap; the unshown left side elevation view being a mirror image thereof;

FIG. 4 is a bottom plan view of the protective liner for a ball cap;

FIG. 5 is a top plan view thereof;

FIG. 6 is a front elevation view thereof; and,

FIG. 7 is a rear elevation view thereof.

The broken lines in the drawings show the environment in which the design is used. The broken lines form no part of the claimed design. 

CLAIM The ornamental design for a protective liner for a ball cap, as shown and described. 